Magnetic system for relays

ABSTRACT

A magnetic system for relays, particularly poled relays, wherein at least one pole shoe covering a portion of a pole surface of a permanent magnet guides the magnetic flow of a particular region of the magnet primarily through a main armature, while the magnetic flow from another particular region of the permanent magnet is guided primarily by way of an auxiliary armature.

United St tesratent 1191 Bosch et-al. I A

1 451 Nov.-27, 1973 ni uxm m mw flame ..nnem Cub .m FKUA 0357 6666 9999 llll 6275 1 i3 827 1 65 I191 l l 333 MAGNETIC SYSTEMFQR RELAYS [75] Inventors: Werner Bosch, Munich; Gerd Sticker, Stuttgart, both of Germany [73] Assignee: Siemens Aktiengesellschaft, Berlin and Munich, Germany May 31, 1972 Appl. No.: 258,411

Great Britain.......1............

Filed:-

Primary Examiner-George Harris Attorney-Benjamin H. Sherman et al. Foreign Application Priority Data- July 7, 1971 [57] ABSTRACT A magnetic system for relays, particularly poled relays, wherein at least one pole shoe coverin Germany........-..........

g a portion of a pole surfaceof a permanent magnet guides the magnetic flow of a particular region of the magnet primarily through'a main armature, while the magnetic flow from another particular region of the permanent 3 "5 m m m} d m m mum C "mm m mm M: m :4 m mTm e mr R a He "ms .1 t C L Smk UI-F ll] 2 00 6 555 5 [[l magnet is guided primarily by way of an auxiliary armature.

- UNITED STATES PATENTS Clare et a1.

335/230 11 Claims, 6 Drawing Figures relay having two stable switching'positions, an electromagneticexcitation winding and at least one permanent magnet for maintaining'the respective electrically 1 provided armature position, wherein the :magnetic current resulting from the superposition of permanent magnetic. current and excitation magneticcurrent 'becomes effective partially by way tofa main armature and partially byway of an auxiliary armature.

2. Description of the; Prior Art- Poledrelays of the general .:ty,pe mentioned above usually exhibit a problemof adjusting ,thenenergy of the permanent magnetifor holding the main armature and the auxiliary armature and the respective spring force of the contactsprings in such ;a way that thedesired 7 current .valuesare; respectively obtained for attraction excitation and 'for drop excitati'omlnithe caseof relays which havebeendesigned for a-certain number of contacts aagiven ratio of theattractionforces,forthe.main :and auxiliary armaturescanjbe.obtained relatively simply by meansof a corresponding construction and ,by means of applying permanentmagnetsiof aparticular strength. However, even in {such cases 1 material and rproduction tolerances will occur a which sometimes require an adjustment of theapermanenttmagnet.

In order to be able'to utilize arelay inasvariednumber of applications .aspossible, however, agmagnetsystem is desired which, depending upon the:particularap- :plication req'uirements, can-be provided with a more or less r large number of spring sets -withoutrequiring .a

.change of construction. In this .instance the holding power in the stableipositions of the-relaymustrbe;adjusted to the respectively effective spring force'srin a poled relay. Since the springs are. oftenibiased .in such va way that they oppose the armature-.forcein one switching direction, ibutcooperate v.with :the armature force in the other switching direction, .the respective holding power'of the permanentmagnetin the two stablepositions must be differentfqr:the;greater number of spring sets whichfmay 'be utilized Iin-arelay. Since, on the other hand, a single permanent magnet-is often provided [due to construction and-economic reasons,

and the single permanent magnet :musthprovide the holding power for both 7 stable positions, the problem arises of renderingthe magnetic forceslforthe;main.-armature and auxiliary armatureeffective .in a different manner.

The German LettersPat'. .No'. 1,188,455 discloses-the rprovision of adjusting :the' holding power; poles .of .the main, armature and of the auxiliary armature independently of each other-for an electromagneticrelay. ln

this prior artarrangement, the adjustmentis effected by means of changingptheairgap atthe auxiliarywarma- :ture, for example, byimeans ofarmechanical bending operation. This, however, 'm'eans ithat @two; operational processes are required-for adjusting *Y-t he vl-r'elayxFirst of all, thewholding magnetic-force :vitselfa-must be -balanced Jinorder to attain-an-adaptation of the permanentymagnet to the numbernofigcontacts andinc-ordersto attaima balance-of tolerancestflnly.afterithisg'first-zoperational .process is accomplished iswthe adjustment-of theratio between themagneticijforcesrattthe:mainiarmature and the-magnetic forces atthe auxiliaryiarmaturereffected by means of amechanical adjustment of the auxiliary armature.

I SUMMARY OF THE INVENTION It is the object of the present invention toprovide a magnetic system for a poled relay of the type mentioned above which can be adjusted to the desired number of contact spring sets and to the desired ratio between the rnainarmature force and the auxiliary armature force in a single operation by means of balancing the permanent magnet whereby. simultaneously production and material tolerances are also balanced.

According to the invention, the foregoing object is achieved in such a way Jthat,-;by means of arranging at least one pole shoe covering a partial pole surface of the permanent magnet or the permanent magnet arrangement, respectively, the magnetic current from a particular partial. region of the permanent magnet or :the permanent magnet. arrangement, respectively, is primarily guided by way of the main armature, andthe rnagnetic current from aparticular otherpartial region is primarilyguided by way of the auxiliary armature. In this manner, it is provided that the two magnetic ranges can be adjustedto given values by external magnetic fields, separately from each other. The two regions of asingle permanent magnet therefore have the effect of two separate magnets since the magnetic current emerging from'theseregions have little influence .on each other'and are therefore essentially independent.

(Therefore-a construction could include two separate permanent magnets which are arranged beside each otherso that they are jointly traversed by the-excitation magnetic current The poleshoe would then cover the pole surface ofoneof the two" permanent magnets and 'thuscausethe same effect as has been described here-' inbefore for a single permanent magnet. In the follow 'ing description, only the more economic construction ,with'a single permanent magnet is particularly set forth and it should therefore be appreciated that two separatepermanent magnets could be employed for the equivalent function. I -In apreferred embodiment of the invention, a permanent magnetis arrangedabove a pole piece of the excitation' coihand polarized in, the direction of the-coilae cess. Hereinafter the magnetic currents will be simply referred to as currents, and should not be confused with the electrical current which traverses the excitation coil. The excitation coil can be envelope in a U-shaped yokewhose centrahportion partially covers a pole surface of thepermanent magnet as apole shoe. Furthermore, an auxiliary .pole plate constructed of soft magneticmaterial can be arranged between the core of the excitation coil and the permanent magnet. A- favorable construction of themagnetic system according to the inventionisrealized wherein the main armature forms a respective operational airsgap with thefree end of the coil core and with the yoke. llhe auxiliary armature is therefore advantageously arranged-at approximately a rightiangle with respectto the main armature so that it,

s in tum, forms operational air gaps with the permanent magnetand with the auxiliary pole piece. According .to .thisyinvention, it is also favorable :if the main armature and'the auxiliary armature are constructed as a single piece. l rln the construction of acfurtherdevelopment ofg the invention, it is.providedrthatrtwoseparatepelegshoesgbe I arranged above the. permanent magnet, oneoftherpole degree is particularly well expressed. In the place of the second pole shoe, the auxiliary armature can be shaped in such a way that it angularly embraces the corresponding portion of the permanent magnet. Preferably, Strontium oxide is utilized as the material for the permanent magnet, since this material can be magnetized extremely wellin the direction of its thicknessso that r,

it can be arranged in a favorable manner as a plate shaped part adjacent one pole of 'the excitation coil without thereby causing excessive dimensions in thedirection generallydcfined by the longitudinal axis of the excitation coil.

BRIEF DESCRIPTIONOF THE DRAWINGS Other objects, features and advantages of the invention, its organization, construction and operation will be best understood from the following detailed description of embodiments thereof taken in conjunction with the accompanying drawings, on which:

FIG. 1 is an elevational view of the basic construction of a magnet system according to the present invention;

FIG. 2 is a perspective view of a magnet system for a practical embodiment of the invention having a U- shaped yoke;

FIG. 3 is an elevational view, in section, of a magnet system having two poleshoes at the permanent magnet;

FIG. 4 is an elevational view, in section, of a magnet system with a poleshoeand an auxiliary armature havmagnet; l

FIG. 5 is an illustration of an arrangement for the magnetic balancing of the permanent magnet particularly showing a magnetic system construction such as illustrated in FIGS. 1 and 2; and

FIG. 6 is an illustration of an arrangement similar to the other magnetic structures, but, which utilizes two permanent magnets. v

' The following description and the correspondingfigures of the drawings areonly directed to the magnet ing a portion which angularlyem'braces the permanent.

' system for a relay in that one skilled in the art will readily appreciate various mounting configurations for pivoting the armatures and supporting spring contacts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, the basic arrangement of a magnet system according to the present invention and the guidance of the current attained thereby is illustrated. The magnet system comprises a coil I wound about a core 2, with a main pole piece 3 disposed at one end thereof and an auxiliary pole piece 4 mounted at the other end thereof. Thecoil l is an excitation coil which is traverse by an electrical current in one direction or the other for producing the attraction and drop excitations of a relay. A permanent magnet 5 is disposed adjacent to the auxiliary pole piece 4 and serves for maintaining therespective armature positions of the relay. The pennanent relay 5 is polarized in-the direction of the longitudinal axis of the coil 1; thereby, the pole surface which is facing away from the coil 1 or the auxiliary pole piece 4, respectively, is partially covered-by a pole shoe 6 which guides a portion of the current from the excitation coil 1- and from the permanent magnet 5 toward the main armature 8 by way of a yoke 7. The main armature 8 is constructed as a single piece with an auxiliary armature 9 and forms an-angle of somewhat more than 90 therewith.

The forces affecting the main armature 8 and the auxiliary armature 9 are produced in the four operational air gaps L1 through L4. Since only a portion of the .permanentmagnet 5 is connected with the yoke 7=,-=-

by way of the pole shoe 6, it'can be magnetically regarded as two parts so that a main permanent magnet part ,5a and an auxiliary permanent m'agnet part 5b can be recognized. The current or flux (#1 which is'produced in the main part 5a of the permanent magnetS therefore closes to a predominant degree by way of the auxiliary pole piece 4, the core -2, the main pole piece 3, the main armature 8, the yoke 7, and the pole shoe 6. Accordingly,'a magnetic force is producedin the main air gaps L1 and L2, between the armature 8 and the main pole piece 3 and the yoke 7, respectively, which affects the main armature 8. The permanent magnet current (b2, however, whichis produced in the auxiliary part 5b of the permanent magnet 5 is guided to the greatest extent to the auxiliary armature 9 by way ofthe auxiliary pole piece 4, and from there back to the auxiliary part 5b, whereby it bridges the air gaps L3 and L4.

/ For switching the relay from one stable position into the other, a current 423 of suitable size and polarity, and which is produced by electrical current flow in the excitation coil 1, is superimposed 'overthe two magnetic currents (b1 and (#2. Depending on the polarity of this control current (#3, either the main permanent magnet current (b1 is augmented and the auxiliary permanent magnet current 412 is weakened, or the opposite occurs sothat, due to the resulting magnetic current in the air gaps L1, L2 and L3, either the main armature 8 or the a permanent magnet 15 as a pole shoe'16. .T he function of such a magnet system has already been described with reference to the structure of FIG.- 1. The differ -ence between these two constructions is seen in the fact that the main armature 18 forms two air gaps with the yoke 17 in the system according to FIG. 2.

FIG. 3 illustrates'a magnet system having a U-shaped yoke as in FIG. 2, but with a slightly different construction. A lateral view has been provided in section whereby the individual parts can still bewell recog-. I

nized. The magnet system again comprises an excitation coil 21 having a core 22, a main pole piece 23 and an auxiliary pole piece 24. A permanent magnet 25 is arranged at the auxiliary pole piece 24, and one of its pole surfaces is partially covered and magnetically connected with the yoke 27 byway of a pole shoe 26. In this manner, a portion of the permanent magnet current is extended from the range 25a of the permanent magnet 25 by way of the main armature 28. As opposed to the constructions illustrated in FIGS. 1 and 2, a pole shoe 26a is also provided and arranged to cover and be magnetically connected to a portion of the aforementioned surface in a second range 25bof the-permanent magnet25. The pole shoe 26a serves to guide'the permanent magnet current from the range 25b toward the auxiliary armature 29. i

In FIG-4 a further embodiment of a magnet system according to the invention 'has been illustrated. This magnetic system is constructed in the same manner as the systems hereinbefore described and has an excitationcoil 31, a core 32,-amain pole=piece33 and an auxiliarypole piece 34. The permanentmagnetcurrent is again guided by'wayof aipole shoe.36 toward a yoke 37 and thus toward a main armature 38 from a range 35a of a permanent magnet 35,,while th'e current from a range 35b of the "magnet 35 closes by way of an auxiliary armature 39. In contrast to the structure illustrated in FIG. 3, a secondpoles hoeis hot provided, however, the auxiliary armature39 comprisesaprojection 39a to provide an angular inclination of the armature which embraces at least the oppositely facing-portions of the auxiliary part 35b of the permanent magnet 35 and therefore provides an auxiliary air gap with respect thereto.

FIG. 5 illustrates a simple arrangement for the mag- V netic balancing of a magnetic system according to the present invention. The magnet system illustrated in ,FIG. 5 is constructed in the same manner as the magnet systems illustrated in FIGS. 1 and 2 and needsonfurther detail descriptionIBy means of coupling a direct magnetic field of suitable strengthto vthe permanent magnet 41, a separate'adjustment of two magnetic portions 41a and 41b is possible. For this'purpose, a magnet coil 42 having a demagnetizing yoke43is applied to the permanent magnet4l or tothepole shoe '44, respectively, in such a way that the field lines of the de-. magnetizing field occur in the main part 41a of the magnet 41, due to the pole shoe 44 andsclosesby way of the auxiliary, pole piece 45 and the-auxiliary part4lb of the permanent magnet-4l toward the other pole of the yoke 43. When a direct field of the illustratedpolarity is applied, the main part 41a of the permanentmagnet 41 is weakened. A repoling causes a decrease of the permanent magnet current'produced by the auxiliary part 41b. Such a magnetic balancing' is also possible with the embodiments of the inventionfillustrated in FIGS. 2 and: and is accomplished in the samemanner.

FIG. 6 illustrates a further embodiment of the magnetic system according to'the present invention. In the previous figures one permanent'magnet-was separated into two regions by a pole shoe which only covers part of the pole surface. This internal magnetic separation is now carried out in FlG.'6'by the provision of two permanent magnets 55a and 55b which are arranged spaced side-by-side and parallel to each other and structed similar to the magneticsystem according to FIG. 1 in that it comprises an excitation winding or coil 7 "51, a core 52 and a-main pole piece 53. A"main armature 58 is effective withthe mainpolepiece'53, while an auxiliary armature 59formsan operational .airgap with the auxiliary pole piece 54. 'Asubdivisionofthe Permanent magnet into two separate partial magnets which, however, arearranged-parallel to-each-other 6 could also be carriedout in the same manner with respect to the constructions according to FIGS. '3and4.

Although we have' described our'invention by reference to certain specific illustrative embodiments, many tion by a direct current of either polarity to produce a respective magnetic current-along the direction of the longitudinal axis ofsaid coil'means; a mainpole at one end of said coil means and an auxiliary pole at the other end of said coil means; permanent magnet means for holding said system in said stable positions, said permanent magnet means having a surface disposed adjacent said auxiliary pole and-including an opposite parallel surface-defining first'and second portions; a yoke dis posed adjacent and extending over the length of said coil means, said yoke including a pole shoe partially coveringsaid opposite surface of and magnetically connected to said first portion of said permanent magnet means; and armature means including a main armature and an auxiliary arrnature,said main armature disposed adjacent said coil means and said yoke and included in a main permanent magnetic circuit which includessaid coilmeans, said first portion of said permanent magnet means and said yoke and said poleshoe, said auxiliary armature disposedadjacent said second portion of said permanent magnet means and included in an auxiliary .magneticcircuit which includes said second portion of said permanentmagnet means, said permanent magnet means poled to produce magnetic current directions in said main and auxiliary magnetic circuits which are respectively aided and opposed in response to excitation of said coil means b'ya direct current of a given polara 2. A magnetsystem according to claim 1, wherein saidauxiliary pole includes aplate of soft magnetic ma- 'terial disposed between said permanent magnet, means and said coil means. t

3. A magnet system according to claim 1, wherein saidpermanent magnet is in the shape of a plate and polarized in'the direction of the thickness of the plate I and theaxis of said coil means.

pieces and said main polepiecerand said yoke define operational air gapswith said main armature.

@6.'A magnet system according to claim 5, wherein said auxiliary armature is arranged at approximately a rightangle with said'main armature and defines operational air gaps with said second portion of saidpermanent magnet and said auxiliary pole piece.

7. Amagnet system according to claim 1, wherein said armature means includes .a. single g piece which comprisessaid main and auxiliary armatures;

current and the permanent magnetic current become effective partially via a main armature and partially via an auxiliary armature, in combination therewith the imthe type having a coil with oppositely disposed poles energizable in either direction longitudinally of the coil to place the relay in its respective stable states, and at least one permanent magnet for holding the relay in a stable state, and wherein the magnetic current flow resulting from the superposition of the excitation magnet provement comprising: at least one pole shoe covering and magnetically connected with only a portion of one I pole surface of the permanent magnet and extending to a point adjacent said main armature, whereby the magnetic current flow of a first region of said magnet is guided primarily via the main armature and the magnetic current flow from a second region of said magnetic is guided primarily via the auxiliary armature, said permanent magnet poled to produce magnetic current directions in the first and second regions and the associated main and auxiliary arrnatures which are respectively aided and opposed in response to energization of said coil in a given direction. 

1. A magnetic system for a relay having two stable switching positions, comprising: coil means for excitation by a direct current of either polarity to produce a respective magnetic current along the direction of the longitudinal axis of said coil means; a main pole at one end of said coil means and an auxiliary pole at the other end of said coil means; permanent magnet means for holding said system in said stable positions, said permanent magnet means having a surface disposed adjacent said auxiliary pole and including an opposite parallel surface defining first and second portions; a yoke disposed adjacent and extending over the length of said coil means, said yoke including a pole shoe partially covering said opposite surface of and magnetically connected to said first portion of said permanent magnet means; and armature means including a main armature and an auxiliary armature, said main armature disposed adjacent said coil means and said yoke and included in a main permanent magnetic circuit which includes said coil means, said first portion of said permanent magnet means and said yoke and said pole shoe, said auxiliary armature disposed adjacent said second portion of said permanent magnet means and included in an auxiliary magnetic circuit which includes said second portion of said permanent magnet means, said permanent magnet means poled to produce magnetic current directions in said main and auxiliary magnetic circuits which are respectively aided and opposed in response to excitation of said coil means by a direct current of a given polarity.
 2. A magnet system according to claim 1, wherein said auxiliary pole includes a plate of soft magnetic material disposed between said permanent magnet means and said coil means.
 3. A magnet system according to claim 1, wherein said permanent magnet is in the shape of a plate and polarized in the direction of the thickness of the plate and the axis of said coil means.
 4. A magnet system according to claim 1, wherein said yoke is U-shaped, said pole shoe being the central leg of the U, and said coil means is disposed between the other legs of the U.
 5. A magnet system according to claim 1, wherein said main and auxiliary poles include respective pole pieces and said main pole piece and said yoke define operational air gaps with said main armature.
 6. A magnet system according to claim 5, wherein said auxiliary armature is arranged at approximately a right angle with said main armature and defines operational air gaps with said second portion of said permanent magnet and said auxiliary pole piece.
 7. A magnet system according to claim 1, wherein said armature means includes a single piece which comprises said main and auxiliary armatures.
 8. A magnetic system according to claim 1, wherein said auxiliary pole comprises a pole piece disposed adjacent and defining an air gap with said auxiliary armature.
 9. A magnet system according to claim 1, wherein said auxiliary armature includes an angularly shaped portion for embracing said second portion of said permanent magnet means.
 10. A magnet system according to claim 1, wherein said permanent magnet means comprises a separate permanent magnet for each of said portions.
 11. In a magnet system for a bistable polar relay of the type having a coil with oppositely disposed poles energizable in either direction longitudinally of the coil to place the relay in its respective stable states, and at least one permanent magnet for holding the relay in a stable state, and wherein the magnetic current flow resulting from the superposition of the excitation magnet current and the permanent magnetic current become effective partially via a main armature and partially via an auxiliary armature, in combination therewith the improvement comprising: at least one pole shoe covering and magnetically connected with only a portion of one pole surface of the permanent magnet and extending to a point adjacent said main armature, whereby the magnetic current flow of a first region of said magnet is guided primarily via the main armature and the magnetic current flow from a second region of said magnetic is guided primarily via the auxiliary armature, said permanent magnet poled to produce magnetic current directions in the first and second regions and the associated main and auxiliary armatures which are respectively aided and opposed in response to energization of said coil in a given direction. 